hi,
i made a mistake lately, writing to an indirectly addressed device in a mitsubishi q series program using an incorrectly initialised index register. since i couldn't just use a search function to locate the operation that was setting it, it took me quite a while to find.
now, it would be handy, if the monitoring software (gx developer in this case) would have a function that even basic debuggers on computers have: to watch some device and tell, where (which program line) it's state/contents has been changed. unfortunately i couldn't really find any information on that in the sad manuals. next i called up the support, but the guy was clueless (it took me half an hour to explain what i wanted to accomplish) in the end he recommended using interrupts but couldn't tell me how to do so.
my questions:
* is it really that uncommon to monitor device changes in PLCs in general and especially on mitsubishi's q series and
* how can you accomplish it?
* debugging inside FBs: that should be theoretically possible, since the FB gets actually inserted in the program that is using it, right? how do i go about that?
* can i find the current line number/instruction number and the program that is currently being executed somewhere?
* can i somehow trigger an exception / interrupt after each step or when some device changes?
* any hints on debugging? i am programming computers for ages but are quite new to PLCs...
thanks in advance, best regards,
Volker.
i made a mistake lately, writing to an indirectly addressed device in a mitsubishi q series program using an incorrectly initialised index register. since i couldn't just use a search function to locate the operation that was setting it, it took me quite a while to find.
now, it would be handy, if the monitoring software (gx developer in this case) would have a function that even basic debuggers on computers have: to watch some device and tell, where (which program line) it's state/contents has been changed. unfortunately i couldn't really find any information on that in the sad manuals. next i called up the support, but the guy was clueless (it took me half an hour to explain what i wanted to accomplish) in the end he recommended using interrupts but couldn't tell me how to do so.
my questions:
* is it really that uncommon to monitor device changes in PLCs in general and especially on mitsubishi's q series and
* how can you accomplish it?
* debugging inside FBs: that should be theoretically possible, since the FB gets actually inserted in the program that is using it, right? how do i go about that?
* can i find the current line number/instruction number and the program that is currently being executed somewhere?
* can i somehow trigger an exception / interrupt after each step or when some device changes?
* any hints on debugging? i am programming computers for ages but are quite new to PLCs...
thanks in advance, best regards,
Volker.